If D.J. Fluker was to begin boxing, he'd need to find gloves first that were big enough.

The average heavyweight trains in 16-ounce gloves. Fluker is not average. Those were too small for the Chargers right tackle, who is 6-foot-5 and 345 pounds with 10.5-inch hands. So, he and boxing coach Dale Soliven drove from Paradise Hills to a mixed-martial arts facility in Pacific Beach, ready to special order ones online if none there would do.

They lucked out.

"We had to go get 18s," Soliven said. "We almost had to get 22s, but I found ones that fit him comfortably."

Fluker is dabbling in some cross-training this offseason, working out with Soliven at the House of Boxing in south San Diego. He hopes the training will help him build on a promising rookie season. The 23-year-old lacks no confidence for it, eager to combine experience with his usual blend of energy and vocalness.

So far, so good. He stood on the Chargers Park practice field Monday with a smile, reporting an early benefit.

"Cardio," Fluker said. "I'm not tired on that field like I used to be."

Soliven has worked for years with Chargers players. His prize student is current Panthers fullback Mike Tolbert, whom Soliven says has real potential in the ring. His other NFL clients have included nose tackle Cam Thomas, defensive tackle Ogemdi Nwagbuo and late safety Paul Oliver.

Always, he wanted to train an offensive lineman.

He believed the footwork in boxing, its lessons in leverage and balance, as well as hand explosion would translate naturally into pass protection. He likes what he's seen thus far from the long-reach Fluker, who's shown to be a quick learner with good athletic ability.

"In boxing, you're either going to sink or swim in your first couple of weeks," Soliven said. "It's a tough sport. … He's learning. The good thing about him is he's super motivated to do it."

The Pro Football Writers of America named Fluker to its all-rookie team in January.

Fluker used the honor to set the tone for his offseason. Shortly after the prize was announced, he took to Twitter and vowed "they have not seen my best yet." Four exclamation marks followed.

One year has made a difference.

At about this time, he was still adjusting to the NFL game speed. Offensive line coach Joe D'Alessandris and veterans worked with him, encouraging the first-round draft pick not to overthink on the field. He would start 17 games, including two in the postseason. His power and motor were partly responsibly for an improved Chargers run game, which saw Ryan Mathews rush for a career-high 1,255 yards.

He is not satisfied.

"I want to get to the Pro Bowl this year," Fluker said. "That's one of my goals. Coach D and I talk about it. I have a lot of potential to do all the right things. … I said, 'They haven't seen my best yet.' What I meant by that was I had a full year under my belt. I understood the game speed. I understood how good I really can be. Now, it's a lot easier. The game is slowing down. …

"This season, it's about bringing it every play. I actually understand the game. I'm actually having fun with this game. I'm actually getting it. I'm not a rookie anymore. They say, 'You've got three more regular-season games before you're not a rookie.' Oh well. I'm going to go out there and play hard regardless because that's the type of guy I am. I'm going to try and get the team riled up because that's what I do. I'm the hype man. Get things done."

Yes, the hype man.

Fluker is more Ali than Frazier, hollering at and imploring teammates before and during games not to be denied. Often, he broke the team huddle at practice. The vocalness was rare from a rookie, the intensity rare from anyone.

But that is Fluker. The new sport is fitting.

He pulls no punches.

"All you need is somebody to give you a little more impact, a little more enthusiasm, a little more fire," Fluker said. "Then, you'll be good. Somebody lights that torch in you, that 'You can do it,' you start buying into it. You start building that bond with yourself that, 'Hey, I can do this. I believe in it. I'm going to die for it. This is what I'm going to do.'

"Every time I'm on the field, that's how I envision it. It's an interview. You never know when you can be replaced. It's all about how you leave your legacy on the field."